Efficient and Stable Graded CsPbI3−xBrx Perovskite Solar Cells and Submodules by Orthogonal Processable Spray Coating

Jin Hyuck Heo, Fei Zhang, Chuanxiao Xiao, Su Jeong Heo, Jin Kyoung Park, Joseph J. Berry, Kai Zhu, Sang Hyuk Im

Research output: Contribution to journalArticlepeer-review

80 Citations (Scopus)


Solution-processed CsPbI2Br thin films often suffer from poor film properties, which are indictive of electronic defects that can lead to poor stability. In addition, significant efforts are required to reduce the large cell-to-module performance gap for inorganic perovskite PV devices. Here, we report the fabrication of inorganic CsPbI2Br-based perovskite thin films with a well-defined CsPbI3−xBrx composition gradient by a scalable, orthogonal processable spray-coating approach. The graded structure broadens the absorption wavelength range, increases carrier lifetime, and facilitates charge separation and collection. With this approach, we demonstrated a monolithically integrated perovskite submodule based on the graded CsPbI3−xBrx by spray coating with an efficiency of 13.82% (112-cm2 aperture area) and ∼9% degradation over 1,000-h continuous 1-sun light soaking.

Original languageEnglish
Pages (from-to)481-494
Number of pages14
Issue number2
Publication statusPublished - 2021 Feb 17

Bibliographical note

Funding Information:
This study was supported by the National Research Foundation of Korea (NRF) under the Ministry of Science, ICT & Future Planning (Basic Science Research Program [no. 2014R1A5A1009799]), Nano-Material Technology Development Program (no. 2017M3A7B4041696), and the Ministry of Trade, Industry & Energy, the Republic of Korea (New & Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning [KETEP]) (no. 20183010013820). The work at the National Renewable Energy Laboratory (NREL) was supported by the U.S. Department of Energy (DOE) under contract no. DE-AC36-08GO28308 with Alliance for Sustainable Energy, LLC, the manager and operator of NREL. The authors acknowledge the support on device fabrication and characterizations from the De-Risking Halide PSCs program of the National Center for Photovoltaics, funded by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Solar Energy Technologies Office. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. government. S.H.I. and K.Z. supervised the research. J.H.H. and F.Z. designed the experiments, carried out the experimental study on device fabrication, and performed basic characterization. C.X. performed the KPFM tests. S.J.H. performed the GIXRD and analyzed the data. J.K.P. performed XPS and UPS measurements. J.J.B. provided guidance on experimental planning and measurement discussion at NREL. J.J.B, K.Z. and S.H.I. wrote and revised this manuscript. All authors made a substantial contribution to the discussion of the content and reviewed and edited the manuscript before submission. The authors declare no competing interests.

Publisher Copyright:
© 2020 Elsevier Inc.


  • CsPbIBr
  • graded structure
  • inorganic perovskite
  • light soaking
  • module
  • orthogonal processability
  • solar cells
  • spray coating
  • stability

ASJC Scopus subject areas

  • General Energy


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